Offline access requires authorization only once or unless user has revoked access. You should use offline access when you want to send prints to printer with out the presence of user or send prints to printer using a cron job script.

Once you hit offlineAccess.php you will be redirected to offlineToken.php which will show you your refresh token.

You need to save refresh token to database, file or some cache systems as later on when you will send print to printer in offline mode you need to replace that refrsh token at line # 29 on cron.php